MAGNETIC-RESONANCE-IMAGING OF LEAVES

Several aspects of leaf anatomy and morphology make it difficult to im age leaves with magnetic resonance imaging. Since most fully expanded leaves contain much intercellular air space and are often thin in one plane, relatively few water protons are available to provide signal. T heir heterogeneous structure and the presence of many air-water interf aces cause imaging problems as a result of differences in magnetic sus ceptibility of tissues and cells. Significant progress has been made i n overcoming these difficulties, primarily by greatly reducing the ech o time, permitting in vivo imaging of leaves at 7 and 9.4 Tesla with a n in-plane resolution of less than 15 mum2. Examples are shown and the potential for gaining information regarding in vivo water relations o f leaves is discussed.